Pre-stressed mill rolls with reverse loading

ABSTRACT

A GAP ADJUSTING DEVICE FOR AN INVERTED SCREW-DOWN PRESSURE PRE-STRESS ROLLING MILL ENABLING COMPENSATION FOR POSSIBLE VARIATIONS IN THE SAID GAP WHEN ROLLING MILL CYLINDERS ARE REPLACED, INCLUDING A JACK HAVING UPPER AND LOWER RAMS ADJUSTABLY SECURED TO ONE ANOTHER TO SELECTIVE-   LY ADJUST THE LENGTH OF THE JACK, ONE OF SAID RAMS BEING OF SELECTIVELY VARIABLE LENGTH IN RESPONSE TO APPLIED PRESSURE FLUID.

Dec. 14, 1971 L, D|OLOT 3,626,738

PRE-STRESSED MILL ROLLS WITH REVERSE LOADING Filed April l1, 1969 2 Sheets-Sheet l.

\ jl'llL//i/H/ lm i Dec. 14, 1971 L, .OLT 3,626,738

PRE-STRESSED MILL ROLLS WITH REVERSE LOADING Filed April 11, 1969 2 Sheets-Sheet 2 United States Patent O 3,626,738 PRE-STRESSED MILL ROLLS WITH REVERSE LOADING Lucien Diolot, Neuilly, France, assgnor to Societe Nouvelle Spidern, Paris, France Filed Apr. 11, 1969, Ser. No. 815,290 Claims priority, application france, Apr. 11, 1968,

Int. cl. zib 31/32 U.S. Cl. '72-237 9 Claims ABSTRACT F THE DISCLOSURE The present invention relates in general to rolling mills, and more particularly to reverse loading arrangement for the rolls in a pre-stressed multi-roll rolling mill.

In French Pat. No. 1,314,562 of Dec. l, 1961, and in the rst document of addition No. 90,470- of May 24, 1966, there is described a novel device intended to provide rapid and effective means of adjustment of the gap between the rolls in a pre-stressed rolling mill. In the different variations constituting the embodiments of the said device, the pre-loading proper of the uprights of the mill housing is obtained by the action of main jacks, called pre-loading jacks. The action of the said jacks is transmitted to the uprights of the housing through the intermediary of supporting chocks (in the case of four-high mills). Under the said action, the various rolls of the mill, particularly the working rolls are loaded, directly or indirectly, against each other with a force greater than the normal loads of the rolling process.

Auxiliary jacks, called reverse loading jacks, are introduced between the supporting chocks, inside the housing. These jacks exert their action in the opposite sense to that of the main jacks; this action tends, in fact, to spread the chocks of the backing rolls, and thus the rolls themselves, apart from each other, and to keep the said spacing constant throughout a rolling operation, due to the mediating action on the said reverse loading jacks of the hydro-mechanical loading device perfected previously by the applicant.

The purpose of the present invention is to effect an improvement in the known device described by the abovereferenced patent and its first addition. The possibility is that it might be desired to modify arbitrarily the gap or spacing between the supporting chocks after having begun the replacement of the mill-rolls, whether they be the backing rolls or the working rolls, and it may also be desired to carry out the operation while, at the same time, maintaining the amount of pre-loading at its initial value. Prior to the invention, adjustments of this kind were obtained by orthodox methods such as jacks, screw and nut drives, or, again, using Wedges.

The invention concerns an improved device which allows adjustment of the gap between the supporting chocks to be carried out in a rapid and reliable manner, thus supplanting the employment of the various other orthodox methods described above. The novel device in accordance with the present inventor furthermore provides the possibility of modifying the amount of pre-loading as required.

The said device is litted, so as to be able to fulfil its function suitable, strut-fashion between the support chocks 3,626,738 Patented Dec. 14, 1971 whose spacing it is intended to adjust. Clearly, several devices are required in the same mill-rolls, in order to secure the requisite evenness in the adjustment which it is proposed to carry out, each of the said devices is positioned against the inner wall of the nearest upright of the housing of the apparatus. A mounting block allows each device to be fixed firmly to the upright of the housing to which it is assembled.

Two rams project from this block, the one supported indirectly from the other, the liirst, in the upper part, the second, in the lower part of the said block, the purpose of each of these rams being to act upon the opposed face of the suport chock corresponding to it. One of the rams, the upper ram for example, is made up of two components sliding one within the other and providing therebetween a space which is in communication with a supply of fluid under high pressure. It is the uppermost component of the said upper ram which makes contact with the chock which is to be moved. The lower component of the same ram is the part which is intended ot provide for the support of the ram assembly upon the lower ram. This latter is con stituted by a single member, capable of executing two dierent movements: rotation about its axis and translation along the former.

By means of the rotational movement which is imposed from the outside, by known methods, upon the said single member of the lower ram, this latter is screwed into the lower component of the upper ram or, contrariwise, is unscrewed, according to the direction of the rotation which was imposed upon it. The translational movement of the said single member is merely a consequence of the rotational movement described.

Use is thus made of two means, independent, constructionally, of each other, but interdependent in the result which they secure, means due to which the desired spacing between the two chocks is obtained. In fact, the pressure of the liquid admitted to the space deiined between the upper and lower components of the upper ram being maintained constant, and the said ram being abutted against the upper support chock, any rotational movement imposed upon the body of the lower ram will tend, according to the direction of this movement, to bring closer together or to spread further apart, the two chocks.

The desired spacing having been obtained, the capability is retained of adjusting the pressure of the fluid so as to adjust, likewise, the amount of pre-loading to a previously specified value. There is no reason, furthermore, why a iirst rapid adjustment of the spacing to be realized should not first be made by controlling accurately the pressure of the fluid, before operatingv the lower ram, making use of the possibility of returning to this member for adjustment, if, having obtained the nal adjustment, it is found necessary to readjust the amount of preloading.

Once the above adjustments are completed, it is advisable to compensate for the deviations from the correct line of rolling which might have resulted from them. Use is made, for this purpose, of sets of wedges, the number of which (one or two) and their positioning depends on the location of the main jack of the apparatus. Thus, when the said jack is placed on the lower part, one of the two sets of wedges is fitted between the upper supporting chock and the cross-member of the upright of the housing corresponding to it, the other set being iitted between the lower cross-member of the housing and the jack concerned; only one set of wedges can equally well be employed, the lower set, for example. When the main jack is situated on the upper part, the corresponding arrangement of the set or sets of wedges is symmetrical with respect to the previous arrangement.

Other particulars and advantages of the invention will appear in the course of the description which follows and from the attached drawings, the description and drawings referring to a preferred embodiment of the invention, which is given purely by way of illustration and is in no way limitative.

FIG. l represents a partial view of a pre-stressed fourhigh rolling mill, fitted with a device in accordance with the invention, in longitudinal section.

FIG. 2 illustrates, on a larger scale, the device in accordance with the invention and, in part, the adjacent components of the rolling mill.

In the figures, the same symbols indicate the same parts in every case. The upright of the stand of rolls, against which the device in accordance with the invention is fixed, is represented by the numeral 1. The supporting chocks 3 and 4 of the backing rolls 5 and 6 are mounted inside the window or opening 2 formed in the stand. The block 9 is anchored firmly to the internal wall of the upright 1, for example, with the aid of a tenon 8, held in a suitable groove 7, cut into the said wall. The face 10 of the block 9, turned towards the inside of the roll-stand, rests againts the webs, which form the part facing it, of the working chocks l1 and 12, chocks corresponding respectively to the rolls 13 and 14.

A longitudinal bore 15, having a vertical axis, holds the two rams of the device, described later. At its lower end, the said bore 15 opens out into successive coaxial bores 16 and 17, whose respective diameters are preferably of increasing size.

The base component 18 of the upper ram of the device may be likened to a hollow piston which slides inside the bore 15. The internal bore 19 of the said hollow piston 18 is tapped, so as to receive the upper part 36, suitably screw-threaded, of the lower ram 38. A joint member 23 and a stuffing-box 24 provide the sealing for the hollow piston 18.

The stem of the hollow piston 18 passes into the internal bore 25 of the upper ram 26, whose lower part forms a second piston of the same diameter as the hollow piston 18, and itself likewise slides within the bore 15 of the block 9, the two working faces of these pistons being arranged to face one another. A sealing jointmember 29 is fitted to the circumference of the said second piston, integral with the upper ram 26. The blind bore 25 of the ram 26 is closed at the Abottom by a cover 30, through which the stem 20` of the hollow piston 18 passes. A compression spring 31 is supported at one end on the said cover a-nd at the other end on a collar 21 secured to the upper end of the stem 20. Due to the effect of this spring, the upper ram 26 is constantly drawn downwards, that is to say, towards the hollow piston 18.

The high-pressure operating fluid is introduced into the space 33 located between the pistons 26 and 18 with the aid of a substantially circular conduit 34 formed in the body of the block 9 and opening through other conduits 35, preferably in the form of longitudinal grooves, into the space 33, which forms a sealed chamber between the two above-mentioned pistons.

In order to avoid undesirable rotation of the upper ram assembly, a rst key 22 is located in a suitable groove formed longitudinally in the stem 20, an accommodating groove being formed, o-n the other hand, in the fixed cover 30. In a similar way, the upper part of the piston 26 carries a key 28, sliding in a groove formed for this purpose in the bore of the cover 32, which serves to close the bore 15, at its upper end.

The head 27 of the ram 26, through which the latter exerts its effort upon the chock 3 also serves as an end stop, when the ram takes up its extreme retracted position. The lower ram 38 also terminates, so as to form the counterpart of the upper ram 26, in a head 40 resting on the lower chock 4.

The cylindrical part of the lower ram 38 comprises, like the part corresponding to it on the upper ram 26, a longitudinal key 39, whose function is to tix the said lower ram against rotational movement, to the gear wheel 41, driven from the outside of the device through the agency of a worm-screw 42. In this way, or any other known manner, the lower ram is caused to turn about its axis, the effect of which is to screw the said lower ram into or out of the tapped thread 19, associated with it, resulting in an axial movement of this lower ram, and, consequently, of the chock against which it abuts. A shoulder 37 or any other equivalent means, serves as an end stop, when the lower ram takes up its extreme position of extension, the said shoulder coming into contact, in the case of the figure, with a ring 43 assembled firmly in the bore 16, i-n the body 1 of the device, A second ring 44, housed in the bore 17 of the said body 1, serves as an end stop for the lower ram, when this latter is situated in its extreme retracted position. In order to permit the free movement in rotation of the lower ram 38 by means of the longitudinal key 39, a bore 45 of an adequate diameter is provided coaxially in the said ring 44.

The main pre-loading jack is shown at 47 in FIG. l, with adjusting wedges 46 being arranged in the case shown in the figure between the said jack 47 and the lower supporting chock 4.

The functioning of the device is as follows.

In the working position, the sealed chamber 33 is constantly under pressure. In order to effect a reduction in the separation existing between the two rams, this pressure is first released. The upper ram 26 is forced downwards, under the action of the spring 31, until its lower face comes into contact with the upper face of the hollow piston 18. During this time, the upper supporting chock 3 will maintain its position assuming that the upper backing and working rolls 5 and 13 still remain in contact. It will be sufficient to create a clearance, at the lower part of the device, equal to that which was obtained as has just been stated. For this purpose, it will be necessary to impart a rotation, in the appropriate direction, to the wormscrew 42, so that the lower ram 38 is screwed into the bore associated with it, until the required reduction is obtained, the corresponding spacing appearing between the head `40 of the lower ram and the lower supporting chock 4.

If the rotation imparted to the ram 38 is continued up to a point where the head 40 abuts against the ring 44, the lower ram is halted in its stroke, and it is now the hollow piston 18, on the contrary, which begins to descend, drawing with it in its movement the uppermost component of the upper ram; this continues until the shoulder 27 on the head of the upper ram comes into contact with the part 32. In this position, the overall height of the device in accordance with the invention is reduced to its minimum.

In the opposite sense, the upper ram can be caused to project upwards, if the position of the supporting chock allows it, -by imparting a rotation in the desired direction to the screw 42, so as to cause the screw-threaded part 36 to unscrew from the tapped part 19; the collar 37 abuts against the ring 43, which results in the raising of the piston 18, and thus of the upper ram. Assuming however, that the ability to introduce pressurized fluid into the sealed chamber 33 is available, this operation is suflicient, for most of the time, to provide the required degree of extension of the upper ram, after having done the same with the lower ram, through the agency of the screw 42.

It should be noted that the housing of the mill-roll stand is subjected to pre-loading, by the sole fact of pressurized fluid being caused to pass into the chamber 33; it would be desirable, in a possible case, to keep the volume of this chamber to the lowest possible value. So as to compensate the disturbances which the above adjustments may have imposed upon the line of rolling, the readjustment of this latter can be obtained by manipulating the adjusting wedges 46.

Needless to say, it would not depart from the framework of the invention, to proceed, for example, to the motorizing of the drive of the screw 42, nor to the auto mating or to the programming of the functioning of the device in accordance with the invention such as by servocontrol in the well-known manner.

This latter offers, amongst oth-er advantages, the elimination of the packing used for adjustment and the freeing of the system from errors' originating especially from variations in the properties of the fluids introduced into the chamber 33, as well as the main jack 47, assuming that the amount of liquid contained can be reduced strictly to a minimum, in each case, in the said chamber 33 as well as in the rolling-mill jacks, and that it is the main jack or the auxiliary jacks which are concerned in serving to maintain and adjust, as required, the spacing between the chocks of the working rolls.

I have shown and described one embodiment in accordance with the present invention. It is understood that the same is not limited thereto but is susceptible of numerous changes and modications as known to a person skilled in the art and I, therefore, do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modications as are obvious to one of ordinary skill in the art.

I claim:

1. In a multi-roll pre-stressed rolling mill having work rolls, backing rolls, upper and lower chocks supporting said backing rolls on either side of said work rolls and housing means including upright supports for accommodating said upper and lower chocks,

apparatus for adjusting and regulating the spacing between the rolls, placed between said upper and lower supporting chocks, comprising:

an upper adjusting member including an upper ram and a piston, slidably engaged within said upper ram along an axis parallel therewith; means for subjecting said upper ram to a rst force and a means for subjecting said piston to a second force opposing said first force, so as to enable the adjustment of said upper ram and said piston according to 1 a predetermined spaced relationship; and.

a lower ram threadingly engaged with said upper adjusting member at the interior portion thereof, whereby the spacing of said rolls may be readily adjusted.

2. Apparatus according to claim 1, wherein said first force subjecting means includes means for providing hydraulic pressure fluid between said upper ram and said piston, whereby the force provided by said hydraulic fluid pressure will tend to increase the spacing between said upper ram and said piston.

3. Apparatus according to claim 1, wherein said second force subjecting means includes a compression spring coupled between said upper ram and said piston, whereby the force provided by said spring will tend to reduce the spacing between said upper ram and said piston.

4. Apparatus according to claim 1, wherein said upper ram includes a longitudinal cylindrical bore, within which said piston is slidably engaged.

5. Apparatus according to claim 3, wherein said upper ram includes a longitudinal cylindrical bore therein, within which said piston is slidably engaged and wherein said upper ram further includes a iirst support surface within said bore for supporting one end of said spring and said piston includes a second support surface disposed within said bore for supporting the other end of said spring.

6. Apparatus according to claim 1, wherein said upper ram includes a first longitudinal key and wherein said housing includes a first grooved member for receiving said lirst key, so as to prevent said upper ram from rotating during displacement along said axis.

7. Apparatus according to claim 1, further including means, engaged within said lower ram, for rotating said lower ram so as to displace said ram along said axis, said rotating means including a gear wheel and a worm-screw coupled therewith for driving said gear wheel, and wherein said lower ram further includes a pair of transverse shoulders separated with respect to each other for limiting the displacement of said lower ram with respect to said upper adjusting member, and wherein said apparatus further includes a pair of rings xed with respect to said housing against which said shoulders are adapted to abut when said lower ram is displaced along said axis.

S. Apparatus according to claim 7, wherein said lower ram further includes a second longitudinal key disposed within a groove provided within said gear wheel, so as to be adjusted to slide therein.

9. Apparatus according to claim 7, wherein said first force subjecting means includes means for providing hydraulic pressure uid between said upper ram and said piston, whereby the force provided by said hydraulic uid pressure will tend to increase the spacing between said upper ram and said piston.

References Cited UNITED STATES PATENTS 12/1969 Stubbs et al. 72-245 3/1970 Stubbs 72-243 U.S. Cl. X.R. 72-245 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3, 626, 738 Dated Deeember 14, 1971 Inventods) Lucien Diolot j It isl certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, lines 2?*43, delete in their entirety and substitute therefor the following housing means including upright supports for accommodating said upper and lower chocks,

apparatus for adjusting and regulating the spacing between the rolls, placed betweensaid upper and lower supporting chocks, comprising:

an upper adjusting member including an upper ram and a piston, slidablyy engaged within said upper ram along an axis parallel therewith;

means for subjecting said upper` ram to a first force and a means for subjecting said piston to a second force opposing said first force,so as to enable the adjustment of said upper ram and said piston according to a predetermined spaced relationship; and

a lower ram threadingly engaged with said upper adjusting member at the interior portion thereof, whereby the spacing of said rolls may be readily adjusted Signed and sealed this 8th day of' August 1972.

(SEAL) Attest:

EDWRD M.IL5JICHER,JR. ROBERT GOTTSCHALS Attesting Officer Commissioner of Patents FORM PO-1050(10-69) USCOMM-DC 60376-F69 1^: u,s, GOVERNMENT PRINTING cFFlcE- 1969 0-366-33.: 

